Sterecon is available at no charge to non-commercial, scientific users. It provides 3-D, stereoscopic contour tracing for segmentation and 3-D geometric measurement of images from SEM, confocal LM, TEM, and tomography. We provide the executable file, menu files, and documentation, but not the source code. A non-disclosure release must be signed. We provide training in the use of Sterecon either remotely (travel paid by the off-site lab) or on-site in Albany. So far, the labs of three collaborators, Robert Summers (B00. of Anatomy, SUNY-Buffalo), Stanley Erlandsen (B00. of Cell Biology and Neuroanatomy, Univ. of Minn. Med. School, Minneapolis) and Andres Kriete (Univ. Giessen, Germany) have received the system. The software has also been distributed to the lab of M. Kirk (Argonne National Laboratory), and to Ted Uyeno (Univ. of Calgary, Canada). The Edge company, manufacturers of a stereoscopic 3-D LM system, recommends Sterecon to its customers Letters of support were written for Ken Eward of BioGrafix, who is applying to the NSF and B00. of Education for additional funding for his cell-visualization computer-graphics teaching tools. A letter of support was written for Stan Erlandsen for an NIH grant application involving use of Sterecon. A paper by one of Sterecon's long-time users was published acknowledging the Resource: Martins, G.G, Summers, R.G., Morrill, J.B. (1998) Cells are added to the archenteron during and following secondary invagination in the sea urchin Lytechinus variegatus. Developmental Biology 198,330-342.